Many people experience back pain with sitting.
In a recent study published in the American Academy of Physical Medicine and Rehabilitation titled : Changes in Lumbar Disk Morphology Associated With Prolonged Sitting Assessed by MagneticResonance Imaging these authors used mid sagittal lumbar magnetic resonance imaging to evaluate continuous sitting and sitting with positional changes every 15 minutes.
They asked subjects in one group to sit continuous for 4 hrs while comparing a group that would stand up every 15 minutes and perform 5 seconds of lumbar flexion, 5 seconds of lumbar extension, 5 seconds of lumbar bending to the right, and then 5 seconds of lumbar bending to the left before returning to a seated position.
They did not find any significant changes in the disc morphology except at L4-5 after day 1 but not day 2 and concluded that L4-5 height changes were not significant with brief positional changes every 15 minutes.
At Dynamic Disc Designs, Dr. Jerome Fryer reviews papers to continue to develop models for professionals. He applauds the authors of this paper and finds the results of the manuscript predictable. He explains ” the discs respond to unloading forces. If one suspects the discs as the pain generator associated with sitting, then postural strategies to improve disc health should include unloading forces” like in his paper, Magnetic resonance imaging and stadiometric assessment of the lumbar discs after sitting and chair-care decompression exercise: a pilot study whereby changes to disc were seen using the upper extremities to unload during positional changes of 15 minutes of sitting
If the net forces with positional changes are in the constant direction of gravity, (I.E, – y ) then the discs do not get a significant break
-Dr. Jerome Fryer explains
He also understands that his research is limited by way of subjects, but continues to see outcomes in practice with this type of off loading strategy.
As we continue to move forward in a world of more sitting, strategies that include off loading of the spine will be of more interest. The intervertebral discs are hydraulic structures that lose up to 25% of height over the course of the day while vertical. Recumbancy and sleep has already showed how these structures recover. Sivian et al. showed in Biorheology how the disc cells behave. If we do not off load the discs, they will not have a chance to recover.
Dynamic Disc Designs continues to develop lumbar models and cervical models to help explain research in hopes to develop better techniques to improve spine health with our ever increasing world of technology and back pain with sitting.